Hi, Pete.
I don't think there is any kind of formal limit in HFTA. The terrain
slopes rapidly down eastward from my QTH at roughly 15% for about a half
mile, maybe 8-10% after that for a couple of miles, and then about 4%
for the next five miles. After that it starts sloping gently upward for
a few miles before hitting a mountain ridge line about 15 miles away
that is just a bit higher than my QTH. I've compared terrain files with
and without that distant ridge line and the impact is definitely
noticeable at low angles. Granted, HFTA says my particular QTH puts out
a lot of energy at very low angles (the major peak is at 2 degrees), so
maybe 4,000 meters is a practical maximum horizon for a more typical
terrain, but I don't think the program constrains itself to any
particular distance.
73,
Dave AB7E
On 5/22/2010 2:44 AM, Pete Smith wrote:
> HFTA only uses terrain out to about 4000 meters.
>
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